This proposal aims to complete preclinical validation and commercialize a novel vaginal packing product based upon a biocompatible polymer hydrogel strategy. The hydrogel will form in situ after being injected into a bag placed within the vaginal cavity during pelvic brachytherapy. The hydrogel packing can then be removed readily after the brachytherapy treatment. This Phase II proposal focuses on preclinical validation of the hydrogel vaginal packing system in vaginal phantoms and cadavers, proof of biocompatibility by an external lab, and clinical trials of vaginal packing during cervical cancer brachytherapy. The hydrogel will serve as vaginal packing material during cervical cancer brachytherapy, displacing rectum and bladder, providing attenuation and stabilizing the applicator. Current alternatives include packing the vagina with gauze, which is uncomfortable for patients, subject to errors and provides limited attenuation of radiation dose, and a commercially available balloon system that is expensive and cumbersome to use. Our innovative polymer hydrogel strategy will provide a simple, customized strategy for vaginal packing that provides attenuation and consistent imaging properties while improving patient comfort and limiting costs. The small business and academic partners will work together to test and commercialize the vaginal packing product for clinical use. The proposed research in phase II will focus on (Aim 1) validation of the hydrogel packing system?s performance in phantoms designed to mimic vaginal cavities, on (Aim 2) evaluation of the biocompatibility of the system and its performance as vaginal packing in soft-curved female cadavers, and on (Aim 3) testing the product in a two-center clinical trial of cervical cancer brachytherapy in 40 human subjects. The phase II research program focuses on generating the evidence needed to support a regulatory application and commercialization of the polymer hydrogel vaginal packing product.